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Researchers develop ideas for improving access for the artificial kidney
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Development of a 24-hour access for patients who want to use a portable, wearable or implantable kidney was an important topic here.
Blood flows can be reduced because patients receive more dialysis each day, but traditional access types used in hemodialysis — central venous catheters, arteriovenous fistulas or grafts — may not be durable enough as patients go about their daily activities.
Central venous catheters (CVCs) have unique problems in what they do to the body’s vascular system as clinicians try to push 400 mL of blood through the catheter during dialysis.
“The problem is that the veins don’t like having plastic tubes in them,” Steven R. Ash, MD, FACP, said during his presentation. “We are making a lot of pathology with these catheters,” referring to the fibrous tissue and sheathing that takes place once the catheter penetrates the vein.
Ash, an Indiana University Health nephrologist and CEO of HemoCleanse Technologies LLC and Ash Access Technology Inc., has been working on the Tributary Venous Access, a device that would allow for blood access without intimal contact or damage, for almost 40 years. The catheter would be inserted into the femoral vein — which is large and can offer a blood flow of 250 mL to 400 mL per minute — and minimize the development of fibrous tissue and sheathing that can clog the vein.
“The Tributary Venous Access device causes less trauma and pathological change compared to a CVC ... the return of the blood could be easily accomplished through a regular catheter because that fibrous tissue or sheathing doesn’t block the return blood,” Ash said. With angiography, the catheter is easy to place, he added.
Creating a needle-free dialysis port for patients using an artificial kidney is a focus for Healionics Corporation. The Seattle, Washington-based company is receiving a $3 million grant from the NIH to develop the device, company CEO Mike Connolly, MS, MBA, said during a presentation at the symposium. “The idea is to be able to affix the port to the skin percutaneously and connect that port body to the natural blood vessels of the patient with a graft,” Connolly said.
The graft connected to the port would be the company’s synthetic STARgraft AV hemodialysis access graft, which has been undergoing clinical trials since April. Healionics received a $1.7 million fast-track small business innovation research grant in 2017 from the National Institute of Diabetes and Digestive and Kidney Diseases in support of regulatory approval and a clinical study of the graft.
Connolly said the aim of the silicone-type STAR material on the exterior of STARgraft is to reduce formation of scar tissue, which the company believes is a major contributor to occlusion of arteriovenous grafts. In a number of preclinical studies looking at grafts with and without the STAR material, “we have seen a substantial reduction in stenosis with STAR-coated arteriovenous grafts,” Connolly said. The coating also helps to reduce infections, a major issue for access.
The human trial of STARgraft is targeted to enroll 50 patients, Connolly said; the primary end point is unassisted patency at 6 months. – by Mark E. Neumann
- References:
- Ash S. Venous blood access without intimal contact or damage: The Tributary Venous Access.
- Connolly M. Improved devices for dialysis access.
Disclosures: Ash reports he is CEO of Ash Access Technology Inc. Connolly reports he is CEO of Healionics Corporation.
Editor's Note: On Oct. 3, 2019, the article was updated to correct the location of Healionics Corporation as well as to add clarification about the STARgraft AV hemodialysis access graft and its clinical trial.